1. Field of the Invention
The present invention relates generally to an apparatus for use in hobby activities involving remote controlled vehicles that uses small internal combustion engines, and more particularly, to an apparatus to be used to control a brushed electric motor driven fuel pump to enable automatic and unattended filling or extraction of fuel from the vehicle's tank.
2. Description of the Background Art
Remote-controlled model aircraft, cars, and other vehicles have become very popular. These remote-controlled model vehicles commonly include an internal combustion engine for propelling the model vehicle. The craft is driven or flown by a pilot who uses an electronic transmitter to send encoded control signals to a receiver that is located inside the craft. These signals are decoded and sent to the appropriate servo mechanism to do the final control action.
The engine used in most cases, is a small internal combustion engine which uses a hydrocarbon liquid as the fuel and as such there is a tank in which an amount to last approximately 10-15 minutes while operating, is stored. Some modelers use a manual hand operated pump to get fuel into or out of the model's tank. In doing so the user generally counts the number of revolutions it takes to fill the tank from an empty state, therefore he has to count each turn his hand makes while filling the tank to get an estimate of the amount used in the previous flight. An overflow tube, attached to the tank, is constantly monitored to know when the tank is full. In most cases the fuel overflows before the pumping is stopped causing spillage and waste.
There are other modelers that use an electrically driven pump (12V) to fill and empty the tank. With such electrically operated devices and systems, the operator actuates a “Forward”/“Stop”/“Reverse” switch to pump fuel into the tank, stop pumping or remove fuel from the tank. Here the user also has to monitor the operation either by listening to the sound of the pump or the overflow to know when to stop the process. Conventional devices and systems using electrically driven pumps does not give the user any information to ascertain the amount of fuel left in a tank after a flight or drive. For instance, U.S. Pat. No. 5,638,803, issued to Chang, describes an oiling control device for remote control model engine oil tanks. Chang describes a method for the automatic filling of a model's fuel tank. This system uses a specially designed check valve, one that will allow air to pass both ways while allowing fuel in only one direction. This check valve is used to prevent fuel flow into the muffler during the filling operation while venting air from the tank. The system described by Chang relies on the effective operation of this check valve to prevent overflow, therefore any failure of the check valve will also result in a very imprecise or improper filling operation. Other fuel pumps and controllers known that fail to adequately and effectively address the foregoing issues include those disclosed in U.S. Pat. Nos. 4,800,859; 4,079,719 and 3,387,404.
The aforementioned prior art devices, systems and methods fail to give the user any information on the amount of fuel left in the craft prior to refilling. This is important as the operator either judges or times the flight duration so that the model does not run out of fuel during operation, resulting in a loss of power and possible damage to the craft as might occur when a sudden landing has to be made.
It can further be seen that conventional methods of filling tanks in fuel operated remote controlled craft result in some fuel being spilled on the ground. This waste precious fuel and leaves patches of damaged grass, especially if the fuel used is gasoline. It is also apparent that because the modeler has to be close to the model to monitor what is happening, he has to stoop or bend for the duration of the filling process as the model is usually close to or on the ground. This is not only uncomfortable and inconvenient but can result in physical injury to the operator.
Given the issues with conventional pumps, there exists a need for an automatic fuel pump for remote controlled toy vehicles operated with fuel, such as model airplanes. It is, therefore, to the effective resolution of the aforementioned problems and shortcomings of the prior art that the present invention is directed. The instant invention addresses this need by providing, without any special attachments, a convenient device, system and means for precisely filling a model craft fuel tank, to a predetermined level without such spills or even the need to monitor the process.